The acronym RFID is taken from the term “Radio-Frequency Identification.” With RFID, an integrated circuit and an antenna are typically combined into a small electronic tag that may be programmed with identifying data or other information. In one example usage scenario, an inventory product code such as a stock-keeping unit (SKU) may be stored by an RFID tag to track inventory in a warehouse or to facilitate customer check-out in a store. An RIFD tag is capable of bidirectional wireless communication using the antenna and a radio frequency (RF) channel for information programming and recall. Hence, information programming of the RFID tag may be effectuated wirelessly by transmitting information to the integrated circuit via the antenna. The information may also be subsequently recalled from the RFID tag using a wireless mechanism.
An RFID reader can be used to communicate wirelessly with an RFID tag. In an example operation, the RFID reader transmits an interrogation signal to the RFID tag and receives a response signal back. At the RFID tag, the received interrogation signal is interpreted as a command to send back the response signal, along with any requested information that the integrated circuit is storing. This exchange of signals between an RFID reader and an RFID tag may be initiated, intentionally or unintentionally, by the RFID reader whenever the RFID reader transmits an interrogation signal in range of the RFID tag. Once a conventional RFID tag is constructed, the conventional RFID tag continues processing and responding to interrogation signals indefinitely.